DRAFT RECOMMENDATION 2.1: OTHER NATURAL EXTERNAL HAZARDS

DRAFT
RECOMMENDATION 2.1: OTHER NATURAL EXTERNAL HAZARDS
PURPOSE
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information request for the
following purposes:
•
To gather information pursuant to Near Term Task Force (NTTF) Recommendation 2.1,
Staff Requirements Memoranda (SRM) associated with SECY-11-0124 and
SECY-11-0137, as amended by the Energy and Water Development and Related
Agencies Appropriations Act of 2012
•
To collect information to facilitate NRC’s determination if there is a need to update the
design basis and systems, structures, and components (SSCs) important to safety to
protect against the updated hazards at operating reactor sites
Pursuant to 10 CFR 50.54(f), addressees are required to submit a written response to this
information request.
BACKGROUND
Present day NRC regulations require structures, systems, and components (SSCs) important to
safety at nuclear power reactors to be designed to withstand the effects of natural phenomena,
including extreme meteorological conditions (i.e., severe weather) such as hurricanes,
tornadoes and waterspouts, thunderstorms, high wind events, lightning, and hail (including
probable maximum size). Power reactor SSCs shall be designed considering the
aforementioned external hazards, without losing their capability to perform their intended safety
functions.
In response to the devastating event in Japan resulting from the earthquake and tsunami and its
impact on the Fukushima Daiichi Nuclear Power Plant, the Commission established a
Near-Term Task Force (NTTF) to conduct a systematic and methodical review of the NRCs
processes and regulations to determine if additional improvements should be made to its
regulatory system. The NTTF, as part of its review, was directed to provide any
recommendations to the Commission for its policy direction, in light of the accident at the
Fukushima Daiichi plant. In examining the accident for insights for reactors in the United States,
the NTTF addressed protecting against accidents resulting from natural phenomena, mitigating
the consequences of such accidents, and ensuring emergency preparedness.
The NTTF made 12 recommendations; in particular, recommendation 2 stated the following:
“The Task Force recommends that the NRC require licensees to reevaluate and
upgrade as necessary the design-basis seismic and flooding protection of SSCs
for each operating reactor.”
Enclosure 3
DRAFT
-2To ensure adequate protection from natural phenomena consistent with the present day state of
knowledge and analytical methods, the Task Force recommended supporting actions to
implement this recommendation to the Commission to prevent fuel damage and to ensure
containment and spent fuel integrity. Of specific concern to this request, recommendation 2.1
states:
“Order licensees to reevaluate the seismic and flooding hazards at their sites
against current NRC requirements and guidance, and if necessary, update the
design basis and SSCs important to safety to protect against the updated
hazards.”
The SRM for SECY-11-093, dated August 19, 2011, directed the staff, by September 9, 2011, to
“identify and make recommendations regarding any NTTF recommendations that can, and in
the staff’s judgment, should be implemented, in part or in whole, without unnecessary delay.” In
SECY-11-0124, “Recommended Actions to be taken without Delay from the Near-Term Task
Force Report,” dated September 9, 2011, the NTTF recommended that 2.1 be completed
without delay. The Commission agreed with the staff’s recommendation to implement 2.1 in
SRM-SECY-11-0124 issued on October 18, 2011, and requested that the staff explain the
meaning of “vulnerability” when issuing the requests for information to licensees pursuant to
10 CFR 50.54(f) to identify actions that have been taken or are planned to address
plant-specific vulnerabilities associated with the reevaluation of seismic and flooding hazards.
The Commission also requested that the staff inform the Commission when it has developed the
technical bases and acceptance criteria for implementing NTTF Recommendation 2.1.
In December 2011, the Energy and Water Development and Related Agencies Appropriations
Act, passed both the House and the Senate making appropriations for the NRC for the
remainder of the fiscal year which started on October 1, 2011. This act specifically added
language directing the NRC to take the following actions:
“The Nuclear Regulatory Commission shall require reactor licensees to
re-evaluate the seismic, tsunami, flooding, and other external hazards at their
sites against current applicable Commission requirements and guidance for such
licenses as expeditiously as possible, and thereafter when appropriate, as
determined by the Commission, and require each licensee to respond to the
Commission that the design basis for each reactor meets the requirements of its
license, current applicable Commission requirements and guidance for such
license”
As a result, the NTTF recommendation 2.1 has been expanded to include other natural hazards
(e.g., meteorological phenomena) that could impact the safety of power reactors in the United
States.
Other background information relevant to this information request includes the individual plant
examinations of external events (IPEEEs). On June 28, 1991, the NRC issued Supplement 4 to
GL 88-20, “Individual Plant Examination of External Events (IPEEE) for Severe Accident
Vulnerabilities,” (ADAMS Accession No. ML031150485) requesting that each licensee identify
and report to the NRC all plant-specific vulnerabilities to severe accidents caused by external
events. The external events to be considered in the IPEEE were seismic events; internal fires;
-3and high winds, floods, and other external initiating events, including accidents related to
transportation or nearby facilities and plant-unique hazards.
NUREG-1742, “Perspectives Gained from the Individual Plant Examination of External Events
(IPEEE) Program,” issued April 2002, (ADAMS Accession Nos. ML021270070 and
ML021270674) provides insights gained by the NRC from the IPEEE program. Almost all
licensees reported in their IPEEE submittals that no plant vulnerabilities were identified with
respect to high winds, floods, and other external events (HFO) (the use of the term
“vulnerability” varied widely among the IPEEE submittals). Most licensees screened out HFO
events on the basis of qualitative assessments, consistent with one of the accepted approaches
given in NUREG-1407, “Procedural and Submittal Guidance for the Individual Plant Examination
of External Events (IPEEE) for Severe Accident Vulnerabilities.” A qualitative assessment
typically involved demonstrating conformance with the 1975 SRP criteria and performing a plant
walkdown. The purpose of the walkdown was to identify any changes to the plant configuration
from the original design basis that might affect the IPEEE evaluation.
None of the 70 IPEEE submittals identified any HFO-related vulnerabilities; however, 34
submittals reported that they had either made, or were considering, a total of 64 HFO-related
plant improvements. Of the 70 submittals, most indicated that some type of walkdown was
performed for HFO events during the IPEEE. The submittals, however, did not provide detailed
descriptions of the walkdown procedures and results. It should be noted that the term
“vulnerability” was not defined in GL88-20. Instead, GL88-20 states that licensees should
provide a discussion on how vulnerability is defined for each external event evaluated.
NUREG-1742 notes that “as a result, the use of the term vulnerability varied widely among the
IPEEE submittals…Some licensees avoided the term altogether, other stated that no
vulnerabilities existed at their plant without defining the word, and still others provided a
definition of vulnerability along with a discussion of their findings.”
REGULATORY REQUIREMENTS
General Design Criterion (GDC) 2, “Design Bases for Protection Against Natural Phenomena,”
in Appendix A to Title 10 of the Code of Federal Regulations, Part 50 (10 CFR Part 50) states,
in part, that SSCs important to safety shall be designed to withstand the effects of natural
phenomena such as tornadoes and hurricanes without loss of capability to perform their safety
functions. The design bases for these SSCs shall reflect appropriate consideration of the most
severe of the natural phenomena that have been historically reported for the site and
surrounding area, with sufficient margin for the limited accuracy, quantity, and period of time in
which the historical data have been accumulated.
GDC 4, “Environmental and Dynamic Effects Design Bases,” of Appendix A to 10 CFR Part 50
requires, in part, that SSCs that are important to safety be adequately protected against the
effects of missiles resulting from events and conditions outside the plant.
GDC 44, “Cooling Water,” of Appendix A to 10 CFR Part 50 states, in part, that a system to
transfer heat from SSCs important to safety to an ultimate heat sink (UHS) shall be provided.
The system safety function shall be to transfer the combined heat load of these SSCs under
normal operating and accident conditions.
-4The regulations concerning reactor site criteria for stationary power reactor site applications filed
on or after January 10, 1997 (Subpart B to 10 CFR Part 100) state, in part, that meteorological
characteristics of the site that are necessary for safety analysis or that may have an impact
upon plant design (such as maximum probable wind speed and precipitation) must be identified
and characterized (§ 100.20(c)(2)). The regulations further state, in part, that the physical
characteristics of the site, including meteorology, must be evaluated and site parameters
established such that potential threats from such physical characteristics will pose no undue risk
to the type of facility proposed to be located at the site (§ 100.21(d)).
DISCUSSION
The Energy and Water Development and Related Agencies Appropriations Act, 2012, directed
NRC to “require reactor licensees to re-evaluate the seismic, tsunami, flooding, and other
external hazards at their sites against current applicable Commission requirements and
guidance for such licensees as expeditiously as possible, and thereafter, when appropriate, as
determined by the Commission, and require each licensee to respond to the Commission that
the design basis for each reactor meets the requirements of its license, current applicable
Commission requirements and guidance for such license.” These other external hazards can
be considered to include meteorological phenomena such as wind and missile loads from
tornadoes and hurricanes, maximum rainfall rates and snow and ice loads for roof design,
extreme maximum and minimum ambient temperatures for normal plant heat sink and
containment heat removal system (post-accident), and meteorological conditions related to the
maximum evaporation and drift loss and minimum water cooling for the ultimate heat sink (UHS)
design.
This Congressional directive will be implemented in two phases as follows:
•
Phase 1: Issue generic 50.54(f) letters to all licensees to reevaluate the external hazards
at their sites against present-day regulatory guidance and methodologies used for ESP
and COL reviews.
•
Phase 2: If necessary, and based upon the results of Phase 1, determine whether
additional regulatory actions are necessary (e.g., update the design basis and SSCs
important to safety) to protect against the updated hazards.
This information request addresses the Phase 1; the Phase 2 will be conducted after receiving
responses to this request.
The scope of the requested information includes the reactor at full power operation and the
spent fuel pool for all modes of operation. The evaluation of the spent fuel pool should consider
each of the various operating configurations of the pool (e.g., full power reactor operations,
refueling outage). Evaluation of ISFSI, if present at the site, is not considered within the scope
at this time. The evaluation of potential loss of ultimate heat sink from the external hazards is
included in the scope.
The first stage of the information requested is related to the hazard evaluation using the current
(present day) NRC requirements and guidance. Because of the experiences gained by both the
NRC and the industry in preparing and reviewing applications of several ESPs and COLs, the
-5technical approaches are well understood. It is anticipated that some interactions will be
required with the industry to reach agreements on implementing the present day requirements
for the operating plants. The time frame outlined under the requested responses takes this into
account. The detailed steps to develop the hazard information are discussed under the
requested actions.
The second stage of the information is related to the identification of actions that will be taken or
planned to be taken to address plant-specific vulnerabilities1 associated with the reevaluation of
the hazard.
REQUESTED ACTIONS
Addressees are being requested to identify the site characteristics that serve as the existing
design basis for natural external hazards (other than seismic and flooding) that can occur at
their site. A list of example site characteristics for external hazards (other than seismic and
flooding) that can adversely impact a facility is provided in Table 1. The list of site
characteristics provide in Table 1 of this document was primarily derived from the list of example
ESP and COL site characteristics provided in Table 1 of Appendix A to SRP 2.0.
Not all of the phenomena listed in Table 1 have corresponding site characteristic values that
serve as a design basis (e.g., thunderstorms, lightning, hail, sand and dust storms, water
spouts, forest and grass fires, volcanic activity). For these phenomena, the addressees should
discuss the frequency of occurrence at their site and the measures taken to ensure the plant is
protected against the adverse effects of the phenomena. The addressees should also identify
any other natural phenomena not listed in Table 1 which can occur at their site for which
protective measures have been implemented.
Addressees are also being requested to identify a new set of site of site characteristic values for
their site using present day NRC guidance. Also included in Table 1 are references to the
guidance documents describing NRC accepted methodologies for deriving each of the new site
characteristic values. Recently approved ESP and COL applications also contain examples of
recently accepted approaches for developing site characteristic values.
For those site characteristics related to meteorological phenomena, the associated site
characteristic values should be based on climatological data that have been updated to include
recent observations.
The design bases for some SSCs are intended to be based on ambient temperatures that will
never be exceeded. In these situations, GDC 2 states that the design bases for SSCs important
to safety shall reflect appropriate consideration of the most severe of the natural phenomena
that have been historically reported for the site and surrounding area, with sufficient margin for
the limited accuracy, quantity, and period of time in which the historical data have been
accumulated. In order to be compliant with GDC 2, the ambient design temperature site
1
A definition of vulnerability in the context of this enclosure is as follows: Plant-specific vulnerabilities are
those features that when subject to the increased demand due to a new hazard evaluation are
degraded or unable to perform their intended functions, which may also lead to compromising the overall
ability to provide protection or mitigation.
-6characteristics should be based on the higher of either historic or 100-year return period values.
Temperatures based on a 100-year return period are considered to provide sufficient margin for
the limited accuracy, quantity, and period of time in which the historical data have been
accumulated as required by the regulation.
A set of site characteristic values not in SRP 2.0 related to the design basis hurricane was
added to Table 1 due to the recent publication of RG 1.221 in October 2011. RG 1.221 is
intended to present hurricane loads that represent an extreme environmental load that is
credible but highly improbable, similar to that of a design basis tornado which has an
exceedance frequency of 10-7 per year. For those sites along the Gulf and Atlantic coasts
where the design basis tornado may not bound the design basis hurricane, addressees are
expected to show that their applicable structures can withstand, independently, the total design
basis tornado load and the total design basis hurricane load as extreme environmental
conditions.
In addition, each addressee is being requested to determine whether the new set of site
characteristic values are bounded by the existing plant design basis. With regards to wind
loads, present day NRC criteria for determining wind loads should be used to ascertain whether
the new wind speed site characteristic values result in higher loads than previously analyzed.
For those sites located near the Gulf or Atlantic coasts, determine whether the wind and missile
loads that would be experienced during the design basis hurricane described in RG 1.221 would
be bounded under the loading analysis for tornadoes.
If the new set of site characteristic values for external hazards are not bounded by the existing
plant design basis, the addressees are being requested to evaluate the impact on applicable
protection and mitigation features in order to identify plant vulnerabilities.
If the new set of site characteristic values for the external hazards listed in Table 1 are not
bounded by the existing plant design basis, each addressee is being asked to evaluate the
impact on the affected protection and mitigation features and determine whether they can
continue to perform their intended functions. If the intended functions cannot be maintained, the
addressee should describe what corrective actions or compensatory measures will be taken.
In developing the new site characteristic values for meteorological hazards, the applicability of
these data to represent site conditions during the expected period of reactor operation should
be substantiated. Any historical meteorological data used to characterize a site should extend
over a significant time interval to capture cyclical extremes. Current literature on possible
changes in the weather in the site region should also be reviewed to be confident that the
methods used to predict weather extremes are reasonable.
REQUESTED INFORMATION
The NRC requests that each addressee provide the information in the steps listed below for
each of its licensed NPP facilities. A flow chart of the requested information is provided in
Figure 1.
1. Identify the site characteristics that serve as the existing design basis for the external
hazards listed in Table 1. Generate a summary of the methodology used to develop
-7each of the existing design bases. Create a list of the SSCs and other measures that
make use of this information and the corresponding FSAR sections and documents
where the SSCs and other measures are discussed.
2. Identify a new set of site characteristic values for the external hazards listed in Table 1
using present day NRC guidance. Generate a summary of the methodology used to
develop each of the new site characteristic values.
3. For each external hazard listed in Table 1, compare the new set of site characteristic
values against the existing plant design bases.
4. Using the comparison performed in Step 3, determine whether the new set of site
characteristic values for the external hazards listed in Table 1 are bounded by the
existing plant design bases. Create a summary of the methodology, including the
walkdown process, used to determine whether the new set of site characteristic values
are bounded by the existing plant design basis. If it is determined that all the new site
characteristic values are bounded by the existing plant design basis, proceed to Step 5.
Otherwise, proceed to Step 6.
5. Submit a report containing the hazard evaluation results that show that all the new site
characteristic values are bounded by the existing plant design basis. Include in this
report the information requested in Steps 1 through 4.2
6. Submit a report containing the hazard evaluation results that show the new site
characteristic values that are bounded and that are not bounded by the existing plant
design basis. Include in this report the information requested in Steps 1 through 4.
7. For those new site characteristic values that are not bounded by the existing plant
design basis, evaluate the impact on applicable protection and mitigation features.
Create a summary of the methodology used to evaluate the impact on applicable
protection and mitigation features.
8. Using the information developed in Step 7, determine whether all the affected protection
and mitigation features can continue to perform their intended functions. Create a
summary of the methodology used to determine whether all affected protection and
mitigation features can continue to perform their intended functions. If it is determined
that all the affected protection mitigation features can continue to perform their intended
functions, proceed to Step 10. Otherwise, proceed to Step 9.
9. If any of the affected protection and mitigation features cannot continue to perform their
intended functions (Step 8), determine what corrective actions or compensatory
measures are necessary. Create a summary of the methodology used to determine what
corrective actions or compensatory measures are necessary.
2
No further action beyond submitting this report is required. Step 5 demonstrates termination of the
process for resolution of NTTF Recommendation 2.1 as amended by the Appropriations Act for 2012.
-810. Submit a report describing how affected features will be able to perform their intended
functions and any corrective actions and compensatory measures that will be necessary.
Include in this report the information requested in Steps 7 through 9.
The information provided in Step 10 will be evaluated in Phase 2 to consider any additional
regulatory actions.
REQUIRED RESPONSE
In accordance with 10 CFR 50.54(f), an addressee must respond as described below:
•
Within XXX (e.g. 180) days of the date of this information request, each addressee is
requested to submit a description of the processes that will be used to (1) evaluate the
impact on applicable protection and mitigation features if new site characteristic values that
are not bounded by the existing plant design basis (Step 7) and (2) determine what
corrective actions or compensatory measures will be necessary if any of the affected
protection and mitigation features cannot continue to perform their intended functions (Step
9). As needed, this time period will allow sufficient time for interactions with the NRC staff
and other stakeholders in development of the processes to assure that there is agreement
on the processes to be used and the needed guidance is developed.
•
Within X (e.g. one) year of the date of this information request, each addressee is requested
to submit a written response consistent with the reports outlined in Steps 5 and 6 above. If
needed, each addressee is also requested to indicate their plans to submitting the report
requested in Step 10 above.
•
If applicable, within X (e.g. two) years of the date of this information request, each
addressee is requested to submit a written response consistent with the report outlined in
Step 10 above.
If an addressee cannot meet the requested response date, the addressee must provide a
response within 90 days of the date of this information request and describe the alternative
course of action that it proposes to take, including the basis of the acceptability of the proposed
alternative course of action and estimated completion dates.
The required written response should be addressed to the U.S. Nuclear Regulatory
Commission, ATTN: Document Control Desk, 11555 Rockville Pike, Rockville, MD 20852,
under oath or affirmation under the provisions of Sections 161.c, 103.b, and 182.a of the Atomic
Energy Act of 1954, as amended, and 10 CFR 50.54(f). In addition, addressees should submit
a copy of the response to the appropriate Regional Administrator.
-9Table 1
Site Characteristics for Natural External Hazards (Other Than Seismic and Flooding)
Phenomena
Present-Day Design Basis Criteria
Design Basis Tornado
• Maximum wind speed
• Maximum pressure drop
• Rate of pressure drop
• Missile spectra
SRP 2.3.1, 3.3.2, and 3.5.1.4; RG 1.76 ( Rev. 1)
Design Basis Hurricane
• Maximum wind speed
• Missile spectra
SRP 3.3.2, and 3.5.1.4; RG 1.221
• If the site-specific hurricane wind speed equals or exceeds
140 mi/h (63 m/s), the licensee should add the design
basis hurricane to its list of new site characteristic values
Severe Wind
• 100-year Wind Speed
SRP 2.3.1 and 3.3.1
Precipitation (for Roof Design)
• Maximum rainfall rate
• Maximum ground snow load for normal winter
precipitation event
• Maximum ground snow load for extreme winter
precipitation event
SRP 2.3.1 and 2.4.2; DC/COL-ISG-7
• The maximum ground snow load for extreme winter
precipitation event should include the contribution from the
normal winter precipitation event
Ambient Design Temperatures
• Dry-bulb temperature and coincident wet-bulb
temperature
2% annual exceedance
1% annual exceedance
100-year maximum
• Dry-bulb temperature
98% annual exceedance
99% annual exceedance
100-year minimum
• Wet-bulb Temperature
2% annual exceedance
1% annual exceedance
100-year maximum
SRP 2.3.1, 5.4.7, 6.2.1, 6.2.2, 6.4, 9.1.3, and 9.2.2,
• These are examples of site characteristic values use in
establishing heat loads for the design of plant heat sink
systems (exclusive of the ultimate heat sink) and plant
heating, ventilation, and air conditioning (HVAC) systems.
Provide only those site characteristic values that have
been used in the design of SSCs important to safety.
• Temperatures based on a 100-year return period are
intended to represent 0% exceedance values (i.e., values
that have a low probability of being exceeded during the
lifetime of plant operation) and are considered to provide
sufficient margin for the limited accuracy, quantity, and
period of time in which the historical data have been
accumulated in accordance with GDC 2.
Ultimate Heat Sink Design Basis
• Conditions Resulting in the Maximum
Evaporation and Drift Loss of Water
During Any Consecutive 30 Days
• Conditions Resulting in the Minimum Water
Cooling
During Any 1 Day
During Any Consecutive 5 Days
• Potential for Water Freezing in the UHS Water
Storage Facility
Potential Frazil and Anchor Ice
Maximum Ice Thickness
Maximum Cumulative Degree-Days Below
Freezing
SRP 2.3.1, 2.4.7, and 9.2.5; RG 1.27 (Rev. 2)
• The meteorological conditions resulting in maximum
evaporation and minimum water cooling should be
identified based on the worst combination of controlling
parameters for the critical time periods unique to the
specific design of the UHS as discussed in RG 1.27.The
meteorological phenomena listed here are examples of site
characteristic values typically used in evaluating
mechanical draft cooling tower UHS.
Identify other phenomena that have been deemed
to be significant for a particular site, such as
thunderstorms, lightning, hail, sand and dust
SRP 2.2.1-2.2.2, 2.2.3 and 2.3.1; RG 1.204
- 10 storms, water spouts, forest and grass fires, and
volcanic activity
- 11 Figure 1
Development of Requested Information and Its Use in Regulatory Analysis
- 12 -
- 13 Enclosure 3 Reference List
10 CFR 50.54(f) – “Conditions of Licenses.”
Recommendations for Enhancing Reactor Safety in the 21st Century: The Near-term Task Force
Review of Insights from the Fukushima Dai-ichi Accident, ML111861807, DATE.
SECY 11-0093, “Near-Term Report and Recommendation for Agency Actions Following Events
in Japan,” ML11186A950, July 12, 2011.
SECY 11-0124, “Recommended Actions to be taken without Delay from the Near-Term Task
Force Report,” ML11245A158, dated September 9, 2011.
SRM SECY 11-0124, “Recommended Action to be taken without Delay from the Near-Term
Task Force Report,” ML112911571, dated October 18, 2011.
SRM SECY 11-0137, “Prioritization of Recommended Actions to Be Taken in Response to
Fukushima Lessons Learned,” ML113490055, dated December 15, 2011.
SRM SECY 11-0093, “Near-Term Report and Recommendation for Agency Actions Following
Events in Japan,” ML112310021, dated August 19, 2011.
Energy and Water Development and Related Agencies Appropriations Act, 2012
Supplement 4 to GL 88-20, “Individual Plant Examination of External Events (IPEEE) for Severe
Accident Vulnerabilities,” ML031150485, June 28, 1991.
NUREG-1742, “Perspectives Gained from the Individual Plant Examination of External Events
(IPEEE) Program,” ML021270070 and ML021270674, issued April 2002.
NUREG-1407, “Procedural and Submittal Guidance for the Individual Plant Examination of
External Events (IPEEE) for Severe Accident Vulnerabilities,” ML063550238, DATE.
“Standard Review Plan [SRP] for the Review of Safety Analysis Reports for Nuclear Power
Plants LWR Edition,” September 1975.
General Design Criterion (GDC) 2, “Design Bases for Protection Against Natural Phenomena,”
in Appendix A to Title 10 of the Code of Federal Regulations, Part 50 (10 CFR Part 50)
General Design Criteria for Nuclear Power Plants, GDC 4, “Environmental and Dynamic Effects
Design Bases,” of Appendix A to 10 CFR Part 50
General Design Criteria for Nuclear Power Plants, GDC 44, “Cooling Water,” of Appendix A to
10 CFR Part 50
Subpart B to 10 CFR Part 100
(§ 100.20(c)(2)
- 14 (§ 100.21(d)).
Table 1 of Appendix A to SRP Section 2.0, “Site Characteristics and Site Parameters,”
ML070400364, March 2007
RG 1.221, “Design-Basis Hurricane and Hurricane Missiles for Nuclear Power Plants,”
ML110940300, October 2011.
RG 1.76, “Design-Basis Tornado and Tornado Missiles for Nuclear Power Plants,”
ML003740273, March 2007.
DC/COL-ISG-7, Interim Staff Guidance on Assessment of Normal and Extreme Winter
Precipitation Loads on the Roof s of Seismic Category I Structures,” ML091490556, July 2009.
RG 1.27, “Ultimate Heat Sink for Nuclear Power Plants,” Revision 2, ML113739969,
January 1976.
RG 1.204, “Guidelines for Lightning Protection of Nuclear Power Plants,” ML052290422,
November 2005.
NUREG-0800, “Standard Review Plan for the Review of Safety Analysis Reports for Nuclear
Power Plants: LWR Edition,” SRP Section:
2.3.1, “Regional Climatology,” ML063600393, March 2007.
3.3.2, Tornado Loadings, ML070570002, March 2007.
3.5.1.4, Missiles Generated by Tornados and Extreme Winds, ML070380174,
March 2007.
3.3.1, Wind Loadings, ML070570001, March 2007.
5.4.7, Residual Heat Removal (RHR) System, ML100680577, May 2010.
6.2.1, Containment Functional Design, ML070220505, March 2007.
6.2.2, Containment Heat Removal Systems, ML070160661, March 2007.
6.4, Control Room Habitability System, ML070550069, March 2007.
9.1.3, Spent Fuel Pool Cooling and Cleanup Systems, ML063190013, March 2007.
9.2.2, Reactor Auxiliary Cooling Water Systems, ML070550053, March 2007.
2.4.2, Floods, ML070100647, March 2007.
2.4.7, Ice Effects, ML070100648, March 2007.
9.2.5, Ultimate Heat Sink, ML070550048, March 2007.
- 15 2.2.1-2.2.2, Identification of Potential Hazards in Site Vicinity, ML070460330,
March 2007
2.2.3, Evaluation of Potential Accidents, ML070460336, March 2007.